---
license: other                     # ⟨FILL: Decision 0.1 — Apache-2.0 (inherited from Qwen3-4B) if open, else 'other' + license_name/link⟩
base_model: Qwen/Qwen3-4B
base_model_relation: finetune
library_name: transformers
pipeline_tag: text-generation
datasets:
  - opera
tags:
  - athena
  - mvrko
  - e-commerce
  - shopping-behavior
  - next-action-prediction
  - large-event-model
  - web-agents
  - lora
  - opera
metrics:
  - exact_match
model-index:
  - name: Athena
    results:
      - task:
          type: next-action-prediction
          name: Next-action prediction
        dataset:
          name: OPeRA (full official test set)
          type: opera
          config: exact-match
        metrics:
          - type: exact_match
            value: 0.2450
            name: Exact-match (n=992)
            verified: false
---

# Athena (4B): a Large Event Model for shopping behavior

**Athena predicts the exact next action a real shopper takes on a live retail page.**
Given the reduced page state and the interaction history, it emits the next action as
structured JSON. On the **full official OPeRA test set (992 actions)** it scores
**24.50% strict exact-match, first among every model tested, ahead of GPT-5.6, Claude
Sonnet 5, and Claude Opus 4.8**, as a 4-billion-parameter model.

Athena is the **base model of the mvrko simulation track**: the accurate, cheap,
self-hostable foundation for agentic shopping, next-action planning, and behavioral
simulation.

- **Developer:** Markopolo AI
- **Model type:** Decoder-only causal LM (dense), LoRA fine-tune of an open base model
- **Base model:** [`Qwen/Qwen3-4B`](https://huggingface.co/Qwen/Qwen3-4B)
- **Modality:** reduced page state + interaction history → next action
  (`action_type`, `semantic_id`, `input_text`)
- **Benchmark:** OPeRA next-action prediction, strict exact-match on the target element
- **Repository:** ⟨FILL: final repo path — Decision 1.5b⟩
- **Release:** ⟨FILL: version string⟩

> Athena is a **fine-tune of an open base model.** The value is the training recipe, the
> observation-space engineering, the 32K long-context supervision, and a specialization a
> general-purpose model cannot reach by prompting. The base weights are the substrate; the
> moat is everything built on top.

---

## TL;DR

| | |
|---|---|
| **Headline** | **24.50% exact-match on OPeRA (full 992)**, #1 vs current frontier |
| **Base** | Qwen3-4B · LoRA r=32, α=32 · 32K context |
| **Output** | Structured next-action JSON (schema below); **98.9%** schema-valid on the 992 |
| **Reproducibility** | Reproduced cold on `transformers 5.5.0` / `torch 2.8.0` / bf16 / greedy |
| **What it is NOT** | It does **not** emit calibrated probabilities. See [Limitations](#limitations) |

---

## Results: full official OPeRA test set (n = 992)

Same test set (`md5 1e02a30d…`), same harness, same strict exact-match scorer for every
model. Frontier models are evaluated zero-shot / prompted; Athena is fine-tuned.

| Model | Params | Exact-match | Δ vs Athena | Margin |
|---|---|---|---|---|
| **Athena (ours, fine-tuned)** | **4B** | **24.50%** | | |
| GPT-5.6 (prompted) | frontier | 22.58% | +1.92 | **parity** (≈1σ, unpaired) |
| *GPT-4.1 (published OPeRA baseline)* | *frontier* | *21.5%* | *+3.0* | *ahead of published SOTA* |
| Claude Sonnet 5 (prompted) | frontier | 18.35% | +6.15 | **separated** (≈3.3σ) |
| Claude Opus 4.8 (prompted) | frontier | 12.70% | +11.80 | **separated** |

**Athena ranks first, ahead of every current-frontier model tested and the published
baseline.**

### Honest statistical read

- **vs Claude Opus 4.8: separated.** +11.8 points, far beyond sampling noise.
- **vs Claude Sonnet 5: separated.** +6.15 points, ≈3.3σ.
- **vs published GPT-4.1 baseline: ahead.** +3.0 points.
- **vs GPT-5.6: statistical parity, nominal edge.** +1.92 points is ≈1σ (unpaired), a
  first-place finish with a nominal lead, **not** a statistically separated one. We report
  it as such. A paired McNemar test on the shared 992 is the correct way to sharpen this
  and is ⟨FILL: pending — Decision 0.2⟩.

> We lead the board **and** state exactly how strong each margin is. Nothing is labeled
> "clear" unless the test supports it.

### The task ceiling: what the frontier numbers reveal

The entire current frontier lands between **12% and 23%** on OPeRA. The ceiling here is the
**difficulty of the task, not model size**: predicting the *exact* element a human clicks,
from dozens of candidates, is genuinely hard, and raw capability barely moves it. Athena's
24.50% is not "low". It is the **best result on a benchmark where the strongest general
models in the world sit below it.** The lever that moves this number is **behavioral
specialization**, not scale.

---

## Why a specialist wins

The frontier models return clean, schema-valid JSON. They understand the task perfectly.
They still lose, because next-action prediction requires knowing *how real shoppers ground
their intent in this interface*, and that knowledge is **behavioral, not linguistic**. A
prompt yields a fluent guess; it cannot supply behavior the model never learned.

> The frontier models are excellent at language. Athena is excellent at shoppers.

**Strongest supporting evidence, the OPeRA error analysis:** the benchmark's own error
taxonomy localizes frontier failure to *grounding* (naming the right element), not
*formatting*. ⟨FILL: cite the specific error-type percentages with the paper section, from
the benchmark source-fact sheet (artifact 1.7). Do not paraphrase from memory.⟩

---

## Architecture and the core innovation: the observation space

The central innovation is not the weights. It is **how the web page is represented to the
model.**

1. **A learned observation space.** Raw HTML is unlearnable at scale, since a single page
   blows past any practical context window. Athena consumes a **structure-preserving
   reduction** that keeps only the *named, actionable* elements (the ones an action can
   target) and discards the rest, turning a sprawling DOM into a compact, typed,
   model-legible page state. This is what makes the next-action target *predictable*
   instead of buried.
2. **Long-context supervision at 32K.** Real sessions carry long histories and large pages;
   Athena trains at a **32,768-token** context so it conditions on the full journey, not a
   truncated snippet.
3. **Behavioral fine-tuning.** Trained directly on what shoppers do over this action space,
   with completion-only masking on the target action.

The **observation-space parser** (or a specification precise enough to rebuild it) is
released so third parties can reproduce the input format. See Reproduction. ⟨FILL: link —
artifact in Part 2⟩

---

## Quickstart

> Copied from a tested script. See Reproduction. Requires `transformers==5.5.0`.

```python
from transformers import AutoModelForCausalLM, AutoTokenizer
import torch, json

REPO = "⟨FILL: repo id⟩"
tok = AutoTokenizer.from_pretrained(REPO, trust_remote_code=True)
mdl = AutoModelForCausalLM.from_pretrained(REPO, dtype=torch.bfloat16,
        device_map="cuda", attn_implementation="sdpa", trust_remote_code=True).eval()

messages = [                       # see example_inputs/ for real OPeRA cases
    {"role": "system",  "content": "⟨exact system string — frozen prompt spec⟩"},
    {"role": "user",    "content": "⟨reduced page state + interaction history⟩\n\n## Next action:"},
]
prompt = tok.apply_chat_template(messages, tokenize=False, add_generation_prompt=True)
enc = tok(prompt, return_tensors="pt", truncation=True, max_length=32768).to("cuda")
out = mdl.generate(**enc, max_new_tokens=96, do_sample=False, pad_token_id=tok.pad_token_id)
print(tok.decode(out[0][enc["input_ids"].shape[1]:], skip_special_tokens=True))
# → {"action_type": "click", "click_type": "product_link", "semantic_id": "..."}
```

---

## Input / output schema

**Output object** (validated on 98.9% of the 992 test outputs):

```json
{"action_type": "click", "click_type": "product_link", "semantic_id": "active_item_list.<product>.product_detail"}
```

- **`action_type`**: enum ⟨FILL: authoritative enum from schema.json (artifact 1.3)⟩
- **`click_type`**: enum ⟨FILL: authoritative enum from schema.json⟩
- **`semantic_id`**: the exact named target element.
- **`input_text`**: present only for `input` actions. ⟨FILL: exact convention on non-input actions⟩

**Scoring:** strict exact-match. Predicted `action_type` **and** `semantic_id` (and
`input_text` for inputs) must equal the ground truth. No partial credit.

---


## Hardware


**Precision:** bf16 throughout (training and evaluation).

**Weights:** ~8 GB on disk (4B parameters, bf16, safetensors), loaded as a single
merged model with no base-model dependency at inference.

**Inference.** Athena runs on a single GPU. The headline evaluation was produced on one
NVIDIA B300 at 32,768-token context with batch size 2, greedy decoding, `sdpa` attention.
A 24 GB card is the practical floor for full 32K-context inference; shorter contexts
(4K to 8K, sufficient for most single-page states) fit comfortably in 16 GB. Memory is
dominated by the bf16 weights plus the KV cache, which grows linearly with context length.

---

## Efficiency

Athena is a **self-hostable 4B** model: 1 to 2 orders of magnitude cheaper per prediction
than prompting a frontier reasoning API, with a **direct answer and no billed reasoning
tokens**, **batched local inference** (no per-call round-trip, no rate limits), and **data
kept in-house**. Exact multiples are computed from the dated cost model. ⟨FILL: efficiency
multiple + pricing date — artifact 1.8⟩

---

## Applications

Each tagged by which family component it requires and by maturity.

| Application | Needs | Maturity |
|---|---|---|
| Next-action prediction / autocomplete of shopper intent | **Athena** (this model) | Benchmarked |
| Session replay: scoring a logged journey step by step | **Athena** (this model) | Benchmarked, this is how the 992-action result is measured |
| Behavioral simulation / free-running journey rollout | **Athena** plus an interactive page-state environment | Not demonstrated. Requires an environment that returns a new page state for a novel action; OPeRA provides logged trajectories only |
| Calibrated conversion / intent scoring | **A different family component** (calibrated intent head, AUC/ECE), **not Athena** | Separate model |

> **Family note:** Athena predicts next actions and is scored on exact match. It does **not**
> emit calibrated probabilities. The calibrated intent head (AUC/ECE) is a **separate
> component** of the mvrko family. See the model family map. Do not attribute calibration
> claims to this model.


---

## Training details

| Setting | Value |
|---|---|
| Base | `Qwen/Qwen3-4B` |
| Method | LoRA (r=32, α=32, dropout 0.1), bf16, gradient checkpointing |
| Target modules | q,k,v,o,gate,up,down proj |
| Context length | 32,768 tokens |
| Objective | completion-only masking on the next-action target |
| Epochs / LR / schedule | 1 / 1e-4 / cosine, warmup 0.03 |
| Hardware | 2× B300, DDP via torchrun |
| Decode (eval) | greedy (deterministic), max_new_tokens 96 |
| ⟨FILL from config.json / training config⟩ | layers, heads, KV heads, head dim, vocab, tokens seen |

---

## Reproduction

The evaluation harness (runner, parser, scorer, **frozen prompt file**), the
observation-space parser, per-example outputs for all models, and 3 to 5 example inputs are
released at markopoloaiinc/Athena-mvrko-4B. Pinned versions and the run record:
`transformers 5.5.0`, `torch 2.8.0+cu129`, bf16, greedy, batch 2. See
`eval_run_record.json`.

**Verification status (Part 3):**
- [x] Cold-start reproduction of the 24.50% headline (indexed, no-dedup, `md5 1e02a30d`).
- [ ] ⟨FILL: cross-engine determinism (transformers↔vLLM agreement rate)⟩
- [ ] ⟨FILL: batch-invariance spot check (bs 1 vs 32)⟩
- [ ] ⟨FILL: fresh-environment quickstart test (< 15 min, by a non-author)⟩
- [ ] ⟨FILL: adversarial read against the OPeRA paper⟩
- [x] Schema validation: 98.9% of 992 outputs validate.

---

## Limitations

- **Fine-tuned vs. prompted.** Athena is fine-tuned on the task; frontier baselines are
  prompted zero-shot. This is a *specialization* comparison, the intended one, not a claim
  about raw model capability.
- **Observation format.** All models are scored on Athena's reduced-HTML observation space;
  the frontier models see it cold. A different encoding could shift their numbers.
- **GPT-5.6 margin is within noise.** +1.92 points at n=992 is a first-place tie with a
  nominal edge, pending a paired test.
- **This benchmark does not evidence calibration.** Exact-match measures grounding accuracy,
  not probability quality. Athena emits no calibrated conversion signal.
- **Strict exact-match is unforgiving** by design. Absolute scores are low because the task
  is hard, not because any model is failing.

---

## Responsible use

⟨FILL: intended-use scope, out-of-scope uses, data-provenance and privacy note, and that
predictions are behavioral estimates, not guarantees.⟩

---

## Related work

- **OPeRA**, the benchmark and its published baselines. ⟨FILL: full citation with the real
  author list copied from arXiv — artifact 1.7⟩
- **RL-based OPeRA methods.** ⟨FILL: name the reinforcement-learning approaches on this
  benchmark explicitly, so the comparison table is not only "us vs. prompted frontier."⟩

---

## License and citation

- **License:** ⟨FILL: Decision 0.1 + the actual LICENSE file. Base `Qwen/Qwen3-4B` is
  Apache-2.0. State inherited obligations if releasing open.⟩
- **Citation:**
  ```bibtex
  @misc{athena_mvrko,
    title  = {Athena: a 4B Large Event Model for shopping-behavior next-action prediction},
    author = {Markopolo AI},
    year   = {2026},
    note   = {Markopolo AI}
  }
  ```
- **Contact:** ⟨FILL⟩

---

*Athena is a 4B Large Event Model that predicts real shopper behavior more accurately than
the current frontier on a public benchmark: cheaply, self-hostably, and with every margin
stated honestly. It is the foundation of the mvrko simulation track.*